Impact time and angle guidance strategy with maximum lateral acceleration constraints: Theory and experiment

• The guidance trajectory is designed by using the Bézier curve, which simultaneously satisfies constraints on impact time, impact angle, and maximum lateral acceleration. The trajectory is parameterized by positioning the control points based on relative distances and angles, which allows for arbitrary initial heading angles and impact angles, enabling omnidirectional launch and strike. Although the guidance laws or trajectories in 11 , 13 , 19 , 20 , and [29] are designed to achieve ITACG, these methods are not suitable for guidance missions involving large initial heading errors or significant impact angles. Moreover, a multi-layer zeroth-order Adam trajectory optimization algorithm is devised to solve the optimization problem of the control parameters without relying on gradient information while achieving a relatively fast convergence rate. • A hyperbolic tangent vector field trajectory tracking guidance algorithm is developed to track the designed trajectory accurately, which can accommodate. scenarios with large initial heading angles, enabling effective trajectory tracking regardless of the initial velocity direction. Although several effective trajectory tracking methods are discussed in [34] and [35] , these methods are limited to cases where the initial velocity direction is constrained to the first and fourth quadrants. Additionally, the trajectory generation problem based on Bézier curves was only explored in [30] and [31] , and closed-loop tracking was not implemented. • Compared with the existing methods in 10 , 11 , 15 , 19 , 22 and [24] , this paper designs an equivalent experimental platform to better validate the effectiveness and hardware adaptability of the proposed guidance strategy. An Impact Time and Angle Control Guidance (ITACG) problem with constraints on maximum lateral acceleration is investigated in this paper. The goal for this problem is to achieve precise interception of a stationary target at the desired impact time and angle, while considering the maximum lateral acceleration constraint during the guidance process. The previous ITACG methods generally struggled to handle a large initial heading error, severely limiting the guidance law’s application scenarios. To tackle this problem and account for the maximum lateral acceleration constraint, an ITACG strategy is proposed from the perspectives of optimal guidance trajectory design and trajectory tracking in this paper. First, a guidance model is formulated, where Bézier curves are used to fit the guidance trajectory, and by parameterizing these curves and analyzing the trajectory constraints in detail, the optimal guidance trajectory design problem is transformed into an optimization problem of the control parameters. Then, a multi-layer zeroth-order Adam trajectory optimization algorithm is introduced to determine the control parameters without relying on gradient information. Subsequently, a hyperbolic tangent vector field trajectory tracking guidance algorithm is proposed to follow the pre-designed trajectory accurately. Finally, numerical simulations and equivalent physical experiments verify the effectiveness of the proposed guidance strategy.